Structural influences on charge carrier dynamics for small-molecule organic photovoltaics

Zhiping Wang, Tetsuhiko Miyadera, Akinori Saeki, Ying Zhou, Shu Seki, Yosei Shibata, Toshihiro Yamanari, Koji Matsubara, Yuji Yoshida

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


We investigated the structural influences on the charge carrier dynamics in zinc phthalocyanine/fullerene (ZnPc/C60) photovoltaic cells by introducing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and 2,5-bis(4-biphenylyl)-bithiophene (BP2T) between indium tin oxide and ZnPc layers. ZnPc films can be tuned to be round, long fiber-like, and short fiber-like structure, respectively. Time-resolved microwave conductivity measurements reveal that charge carrier lifetime in ZnPc/C60 bilayer films is considerably affected by the intra-grain properties. Transient photocurrent of ZnPc single films indicated that the charge carriers can transport for a longer distance in the long fiber-like grains than that in the round grains, due to the greatly lessened grain boundaries. By carefully controlling the structure of ZnPc films, the short-circuit current and fill factor of a ZnPc/C60 heterojunction solar cell with BP2T are significantly improved and the power conversion efficiency is increased to 2.6%, which is 120% larger than the conventional cell without BP2T.

Original languageEnglish
Article number013105
JournalJournal of Applied Physics
Issue number1
Publication statusPublished - 2014 Jul 7
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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